A common factor that connects Ayan Mukerji`s maiden film `Wake Up Sid!`, `Yeh Jawaani Hai Deewani` and his upcoming magnum opus `Brahmastra ` is Bollywood star Ranbir Kapoor. The filmmaker minces no words in calling his "good friend" amazing and has revealed as to why the actor is a key part in all his movies.

In a conversation with IANS, Ayan said: "Well, Ranbir is amazing... He is genuinely an actor whose craft is really admired and I am fortunate enough that when we met on `Wake Up Sid!` we became very good friends and we also understand each other very well at work."